1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * Basic worker thread pool for io_uring |
4 | * |
5 | * Copyright (C) 2019 Jens Axboe |
6 | * |
7 | */ |
8 | #include <linux/kernel.h> |
9 | #include <linux/init.h> |
10 | #include <linux/errno.h> |
11 | #include <linux/sched/signal.h> |
12 | #include <linux/percpu.h> |
13 | #include <linux/slab.h> |
14 | #include <linux/rculist_nulls.h> |
15 | #include <linux/cpu.h> |
16 | #include <linux/task_work.h> |
17 | #include <linux/audit.h> |
18 | #include <linux/mmu_context.h> |
19 | #include <uapi/linux/io_uring.h> |
20 | |
21 | #include "io-wq.h" |
22 | #include "slist.h" |
23 | #include "io_uring.h" |
24 | |
25 | #define WORKER_IDLE_TIMEOUT (5 * HZ) |
26 | |
27 | enum { |
28 | IO_WORKER_F_UP = 1, /* up and active */ |
29 | IO_WORKER_F_RUNNING = 2, /* account as running */ |
30 | IO_WORKER_F_FREE = 4, /* worker on free list */ |
31 | IO_WORKER_F_BOUND = 8, /* is doing bounded work */ |
32 | }; |
33 | |
34 | enum { |
35 | IO_WQ_BIT_EXIT = 0, /* wq exiting */ |
36 | }; |
37 | |
38 | enum { |
39 | IO_ACCT_STALLED_BIT = 0, /* stalled on hash */ |
40 | }; |
41 | |
42 | /* |
43 | * One for each thread in a wq pool |
44 | */ |
45 | struct io_worker { |
46 | refcount_t ref; |
47 | unsigned flags; |
48 | struct hlist_nulls_node nulls_node; |
49 | struct list_head all_list; |
50 | struct task_struct *task; |
51 | struct io_wq *wq; |
52 | |
53 | struct io_wq_work *cur_work; |
54 | struct io_wq_work *next_work; |
55 | raw_spinlock_t lock; |
56 | |
57 | struct completion ref_done; |
58 | |
59 | unsigned long create_state; |
60 | struct callback_head create_work; |
61 | int create_index; |
62 | |
63 | union { |
64 | struct rcu_head rcu; |
65 | struct work_struct work; |
66 | }; |
67 | }; |
68 | |
69 | #if BITS_PER_LONG == 64 |
70 | #define IO_WQ_HASH_ORDER 6 |
71 | #else |
72 | #define IO_WQ_HASH_ORDER 5 |
73 | #endif |
74 | |
75 | #define IO_WQ_NR_HASH_BUCKETS (1u << IO_WQ_HASH_ORDER) |
76 | |
77 | struct io_wq_acct { |
78 | unsigned nr_workers; |
79 | unsigned max_workers; |
80 | int index; |
81 | atomic_t nr_running; |
82 | raw_spinlock_t lock; |
83 | struct io_wq_work_list work_list; |
84 | unsigned long flags; |
85 | }; |
86 | |
87 | enum { |
88 | IO_WQ_ACCT_BOUND, |
89 | IO_WQ_ACCT_UNBOUND, |
90 | IO_WQ_ACCT_NR, |
91 | }; |
92 | |
93 | /* |
94 | * Per io_wq state |
95 | */ |
96 | struct io_wq { |
97 | unsigned long state; |
98 | |
99 | free_work_fn *free_work; |
100 | io_wq_work_fn *do_work; |
101 | |
102 | struct io_wq_hash *hash; |
103 | |
104 | atomic_t worker_refs; |
105 | struct completion worker_done; |
106 | |
107 | struct hlist_node cpuhp_node; |
108 | |
109 | struct task_struct *task; |
110 | |
111 | struct io_wq_acct acct[IO_WQ_ACCT_NR]; |
112 | |
113 | /* lock protects access to elements below */ |
114 | raw_spinlock_t lock; |
115 | |
116 | struct hlist_nulls_head free_list; |
117 | struct list_head all_list; |
118 | |
119 | struct wait_queue_entry wait; |
120 | |
121 | struct io_wq_work *hash_tail[IO_WQ_NR_HASH_BUCKETS]; |
122 | |
123 | cpumask_var_t cpu_mask; |
124 | }; |
125 | |
126 | static enum cpuhp_state io_wq_online; |
127 | |
128 | struct io_cb_cancel_data { |
129 | work_cancel_fn *fn; |
130 | void *data; |
131 | int nr_running; |
132 | int nr_pending; |
133 | bool cancel_all; |
134 | }; |
135 | |
136 | static bool create_io_worker(struct io_wq *wq, int index); |
137 | static void io_wq_dec_running(struct io_worker *worker); |
138 | static bool io_acct_cancel_pending_work(struct io_wq *wq, |
139 | struct io_wq_acct *acct, |
140 | struct io_cb_cancel_data *match); |
141 | static void create_worker_cb(struct callback_head *cb); |
142 | static void io_wq_cancel_tw_create(struct io_wq *wq); |
143 | |
144 | static bool io_worker_get(struct io_worker *worker) |
145 | { |
146 | return refcount_inc_not_zero(r: &worker->ref); |
147 | } |
148 | |
149 | static void io_worker_release(struct io_worker *worker) |
150 | { |
151 | if (refcount_dec_and_test(r: &worker->ref)) |
152 | complete(&worker->ref_done); |
153 | } |
154 | |
155 | static inline struct io_wq_acct *io_get_acct(struct io_wq *wq, bool bound) |
156 | { |
157 | return &wq->acct[bound ? IO_WQ_ACCT_BOUND : IO_WQ_ACCT_UNBOUND]; |
158 | } |
159 | |
160 | static inline struct io_wq_acct *io_work_get_acct(struct io_wq *wq, |
161 | struct io_wq_work *work) |
162 | { |
163 | return io_get_acct(wq, bound: !(work->flags & IO_WQ_WORK_UNBOUND)); |
164 | } |
165 | |
166 | static inline struct io_wq_acct *io_wq_get_acct(struct io_worker *worker) |
167 | { |
168 | return io_get_acct(wq: worker->wq, bound: worker->flags & IO_WORKER_F_BOUND); |
169 | } |
170 | |
171 | static void io_worker_ref_put(struct io_wq *wq) |
172 | { |
173 | if (atomic_dec_and_test(v: &wq->worker_refs)) |
174 | complete(&wq->worker_done); |
175 | } |
176 | |
177 | bool io_wq_worker_stopped(void) |
178 | { |
179 | struct io_worker *worker = current->worker_private; |
180 | |
181 | if (WARN_ON_ONCE(!io_wq_current_is_worker())) |
182 | return true; |
183 | |
184 | return test_bit(IO_WQ_BIT_EXIT, &worker->wq->state); |
185 | } |
186 | |
187 | static void io_worker_cancel_cb(struct io_worker *worker) |
188 | { |
189 | struct io_wq_acct *acct = io_wq_get_acct(worker); |
190 | struct io_wq *wq = worker->wq; |
191 | |
192 | atomic_dec(v: &acct->nr_running); |
193 | raw_spin_lock(&wq->lock); |
194 | acct->nr_workers--; |
195 | raw_spin_unlock(&wq->lock); |
196 | io_worker_ref_put(wq); |
197 | clear_bit_unlock(nr: 0, addr: &worker->create_state); |
198 | io_worker_release(worker); |
199 | } |
200 | |
201 | static bool io_task_worker_match(struct callback_head *cb, void *data) |
202 | { |
203 | struct io_worker *worker; |
204 | |
205 | if (cb->func != create_worker_cb) |
206 | return false; |
207 | worker = container_of(cb, struct io_worker, create_work); |
208 | return worker == data; |
209 | } |
210 | |
211 | static void io_worker_exit(struct io_worker *worker) |
212 | { |
213 | struct io_wq *wq = worker->wq; |
214 | |
215 | while (1) { |
216 | struct callback_head *cb = task_work_cancel_match(task: wq->task, |
217 | match: io_task_worker_match, data: worker); |
218 | |
219 | if (!cb) |
220 | break; |
221 | io_worker_cancel_cb(worker); |
222 | } |
223 | |
224 | io_worker_release(worker); |
225 | wait_for_completion(&worker->ref_done); |
226 | |
227 | raw_spin_lock(&wq->lock); |
228 | if (worker->flags & IO_WORKER_F_FREE) |
229 | hlist_nulls_del_rcu(n: &worker->nulls_node); |
230 | list_del_rcu(entry: &worker->all_list); |
231 | raw_spin_unlock(&wq->lock); |
232 | io_wq_dec_running(worker); |
233 | /* |
234 | * this worker is a goner, clear ->worker_private to avoid any |
235 | * inc/dec running calls that could happen as part of exit from |
236 | * touching 'worker'. |
237 | */ |
238 | current->worker_private = NULL; |
239 | |
240 | kfree_rcu(worker, rcu); |
241 | io_worker_ref_put(wq); |
242 | do_exit(error_code: 0); |
243 | } |
244 | |
245 | static inline bool __io_acct_run_queue(struct io_wq_acct *acct) |
246 | { |
247 | return !test_bit(IO_ACCT_STALLED_BIT, &acct->flags) && |
248 | !wq_list_empty(&acct->work_list); |
249 | } |
250 | |
251 | /* |
252 | * If there's work to do, returns true with acct->lock acquired. If not, |
253 | * returns false with no lock held. |
254 | */ |
255 | static inline bool io_acct_run_queue(struct io_wq_acct *acct) |
256 | __acquires(&acct->lock) |
257 | { |
258 | raw_spin_lock(&acct->lock); |
259 | if (__io_acct_run_queue(acct)) |
260 | return true; |
261 | |
262 | raw_spin_unlock(&acct->lock); |
263 | return false; |
264 | } |
265 | |
266 | /* |
267 | * Check head of free list for an available worker. If one isn't available, |
268 | * caller must create one. |
269 | */ |
270 | static bool io_wq_activate_free_worker(struct io_wq *wq, |
271 | struct io_wq_acct *acct) |
272 | __must_hold(RCU) |
273 | { |
274 | struct hlist_nulls_node *n; |
275 | struct io_worker *worker; |
276 | |
277 | /* |
278 | * Iterate free_list and see if we can find an idle worker to |
279 | * activate. If a given worker is on the free_list but in the process |
280 | * of exiting, keep trying. |
281 | */ |
282 | hlist_nulls_for_each_entry_rcu(worker, n, &wq->free_list, nulls_node) { |
283 | if (!io_worker_get(worker)) |
284 | continue; |
285 | if (io_wq_get_acct(worker) != acct) { |
286 | io_worker_release(worker); |
287 | continue; |
288 | } |
289 | /* |
290 | * If the worker is already running, it's either already |
291 | * starting work or finishing work. In either case, if it does |
292 | * to go sleep, we'll kick off a new task for this work anyway. |
293 | */ |
294 | wake_up_process(tsk: worker->task); |
295 | io_worker_release(worker); |
296 | return true; |
297 | } |
298 | |
299 | return false; |
300 | } |
301 | |
302 | /* |
303 | * We need a worker. If we find a free one, we're good. If not, and we're |
304 | * below the max number of workers, create one. |
305 | */ |
306 | static bool io_wq_create_worker(struct io_wq *wq, struct io_wq_acct *acct) |
307 | { |
308 | /* |
309 | * Most likely an attempt to queue unbounded work on an io_wq that |
310 | * wasn't setup with any unbounded workers. |
311 | */ |
312 | if (unlikely(!acct->max_workers)) |
313 | pr_warn_once("io-wq is not configured for unbound workers" ); |
314 | |
315 | raw_spin_lock(&wq->lock); |
316 | if (acct->nr_workers >= acct->max_workers) { |
317 | raw_spin_unlock(&wq->lock); |
318 | return true; |
319 | } |
320 | acct->nr_workers++; |
321 | raw_spin_unlock(&wq->lock); |
322 | atomic_inc(v: &acct->nr_running); |
323 | atomic_inc(v: &wq->worker_refs); |
324 | return create_io_worker(wq, index: acct->index); |
325 | } |
326 | |
327 | static void io_wq_inc_running(struct io_worker *worker) |
328 | { |
329 | struct io_wq_acct *acct = io_wq_get_acct(worker); |
330 | |
331 | atomic_inc(v: &acct->nr_running); |
332 | } |
333 | |
334 | static void create_worker_cb(struct callback_head *cb) |
335 | { |
336 | struct io_worker *worker; |
337 | struct io_wq *wq; |
338 | |
339 | struct io_wq_acct *acct; |
340 | bool do_create = false; |
341 | |
342 | worker = container_of(cb, struct io_worker, create_work); |
343 | wq = worker->wq; |
344 | acct = &wq->acct[worker->create_index]; |
345 | raw_spin_lock(&wq->lock); |
346 | |
347 | if (acct->nr_workers < acct->max_workers) { |
348 | acct->nr_workers++; |
349 | do_create = true; |
350 | } |
351 | raw_spin_unlock(&wq->lock); |
352 | if (do_create) { |
353 | create_io_worker(wq, index: worker->create_index); |
354 | } else { |
355 | atomic_dec(v: &acct->nr_running); |
356 | io_worker_ref_put(wq); |
357 | } |
358 | clear_bit_unlock(nr: 0, addr: &worker->create_state); |
359 | io_worker_release(worker); |
360 | } |
361 | |
362 | static bool io_queue_worker_create(struct io_worker *worker, |
363 | struct io_wq_acct *acct, |
364 | task_work_func_t func) |
365 | { |
366 | struct io_wq *wq = worker->wq; |
367 | |
368 | /* raced with exit, just ignore create call */ |
369 | if (test_bit(IO_WQ_BIT_EXIT, &wq->state)) |
370 | goto fail; |
371 | if (!io_worker_get(worker)) |
372 | goto fail; |
373 | /* |
374 | * create_state manages ownership of create_work/index. We should |
375 | * only need one entry per worker, as the worker going to sleep |
376 | * will trigger the condition, and waking will clear it once it |
377 | * runs the task_work. |
378 | */ |
379 | if (test_bit(0, &worker->create_state) || |
380 | test_and_set_bit_lock(nr: 0, addr: &worker->create_state)) |
381 | goto fail_release; |
382 | |
383 | atomic_inc(v: &wq->worker_refs); |
384 | init_task_work(twork: &worker->create_work, func); |
385 | worker->create_index = acct->index; |
386 | if (!task_work_add(task: wq->task, twork: &worker->create_work, mode: TWA_SIGNAL)) { |
387 | /* |
388 | * EXIT may have been set after checking it above, check after |
389 | * adding the task_work and remove any creation item if it is |
390 | * now set. wq exit does that too, but we can have added this |
391 | * work item after we canceled in io_wq_exit_workers(). |
392 | */ |
393 | if (test_bit(IO_WQ_BIT_EXIT, &wq->state)) |
394 | io_wq_cancel_tw_create(wq); |
395 | io_worker_ref_put(wq); |
396 | return true; |
397 | } |
398 | io_worker_ref_put(wq); |
399 | clear_bit_unlock(nr: 0, addr: &worker->create_state); |
400 | fail_release: |
401 | io_worker_release(worker); |
402 | fail: |
403 | atomic_dec(v: &acct->nr_running); |
404 | io_worker_ref_put(wq); |
405 | return false; |
406 | } |
407 | |
408 | static void io_wq_dec_running(struct io_worker *worker) |
409 | { |
410 | struct io_wq_acct *acct = io_wq_get_acct(worker); |
411 | struct io_wq *wq = worker->wq; |
412 | |
413 | if (!(worker->flags & IO_WORKER_F_UP)) |
414 | return; |
415 | |
416 | if (!atomic_dec_and_test(v: &acct->nr_running)) |
417 | return; |
418 | if (!io_acct_run_queue(acct)) |
419 | return; |
420 | |
421 | raw_spin_unlock(&acct->lock); |
422 | atomic_inc(v: &acct->nr_running); |
423 | atomic_inc(v: &wq->worker_refs); |
424 | io_queue_worker_create(worker, acct, func: create_worker_cb); |
425 | } |
426 | |
427 | /* |
428 | * Worker will start processing some work. Move it to the busy list, if |
429 | * it's currently on the freelist |
430 | */ |
431 | static void __io_worker_busy(struct io_wq *wq, struct io_worker *worker) |
432 | { |
433 | if (worker->flags & IO_WORKER_F_FREE) { |
434 | worker->flags &= ~IO_WORKER_F_FREE; |
435 | raw_spin_lock(&wq->lock); |
436 | hlist_nulls_del_init_rcu(n: &worker->nulls_node); |
437 | raw_spin_unlock(&wq->lock); |
438 | } |
439 | } |
440 | |
441 | /* |
442 | * No work, worker going to sleep. Move to freelist. |
443 | */ |
444 | static void __io_worker_idle(struct io_wq *wq, struct io_worker *worker) |
445 | __must_hold(wq->lock) |
446 | { |
447 | if (!(worker->flags & IO_WORKER_F_FREE)) { |
448 | worker->flags |= IO_WORKER_F_FREE; |
449 | hlist_nulls_add_head_rcu(n: &worker->nulls_node, h: &wq->free_list); |
450 | } |
451 | } |
452 | |
453 | static inline unsigned int io_get_work_hash(struct io_wq_work *work) |
454 | { |
455 | return work->flags >> IO_WQ_HASH_SHIFT; |
456 | } |
457 | |
458 | static bool io_wait_on_hash(struct io_wq *wq, unsigned int hash) |
459 | { |
460 | bool ret = false; |
461 | |
462 | spin_lock_irq(lock: &wq->hash->wait.lock); |
463 | if (list_empty(head: &wq->wait.entry)) { |
464 | __add_wait_queue(wq_head: &wq->hash->wait, wq_entry: &wq->wait); |
465 | if (!test_bit(hash, &wq->hash->map)) { |
466 | __set_current_state(TASK_RUNNING); |
467 | list_del_init(entry: &wq->wait.entry); |
468 | ret = true; |
469 | } |
470 | } |
471 | spin_unlock_irq(lock: &wq->hash->wait.lock); |
472 | return ret; |
473 | } |
474 | |
475 | static struct io_wq_work *io_get_next_work(struct io_wq_acct *acct, |
476 | struct io_worker *worker) |
477 | __must_hold(acct->lock) |
478 | { |
479 | struct io_wq_work_node *node, *prev; |
480 | struct io_wq_work *work, *tail; |
481 | unsigned int stall_hash = -1U; |
482 | struct io_wq *wq = worker->wq; |
483 | |
484 | wq_list_for_each(node, prev, &acct->work_list) { |
485 | unsigned int hash; |
486 | |
487 | work = container_of(node, struct io_wq_work, list); |
488 | |
489 | /* not hashed, can run anytime */ |
490 | if (!io_wq_is_hashed(work)) { |
491 | wq_list_del(list: &acct->work_list, node, prev); |
492 | return work; |
493 | } |
494 | |
495 | hash = io_get_work_hash(work); |
496 | /* all items with this hash lie in [work, tail] */ |
497 | tail = wq->hash_tail[hash]; |
498 | |
499 | /* hashed, can run if not already running */ |
500 | if (!test_and_set_bit(nr: hash, addr: &wq->hash->map)) { |
501 | wq->hash_tail[hash] = NULL; |
502 | wq_list_cut(list: &acct->work_list, last: &tail->list, prev); |
503 | return work; |
504 | } |
505 | if (stall_hash == -1U) |
506 | stall_hash = hash; |
507 | /* fast forward to a next hash, for-each will fix up @prev */ |
508 | node = &tail->list; |
509 | } |
510 | |
511 | if (stall_hash != -1U) { |
512 | bool unstalled; |
513 | |
514 | /* |
515 | * Set this before dropping the lock to avoid racing with new |
516 | * work being added and clearing the stalled bit. |
517 | */ |
518 | set_bit(nr: IO_ACCT_STALLED_BIT, addr: &acct->flags); |
519 | raw_spin_unlock(&acct->lock); |
520 | unstalled = io_wait_on_hash(wq, hash: stall_hash); |
521 | raw_spin_lock(&acct->lock); |
522 | if (unstalled) { |
523 | clear_bit(nr: IO_ACCT_STALLED_BIT, addr: &acct->flags); |
524 | if (wq_has_sleeper(wq_head: &wq->hash->wait)) |
525 | wake_up(&wq->hash->wait); |
526 | } |
527 | } |
528 | |
529 | return NULL; |
530 | } |
531 | |
532 | static void io_assign_current_work(struct io_worker *worker, |
533 | struct io_wq_work *work) |
534 | { |
535 | if (work) { |
536 | io_run_task_work(); |
537 | cond_resched(); |
538 | } |
539 | |
540 | raw_spin_lock(&worker->lock); |
541 | worker->cur_work = work; |
542 | worker->next_work = NULL; |
543 | raw_spin_unlock(&worker->lock); |
544 | } |
545 | |
546 | /* |
547 | * Called with acct->lock held, drops it before returning |
548 | */ |
549 | static void io_worker_handle_work(struct io_wq_acct *acct, |
550 | struct io_worker *worker) |
551 | __releases(&acct->lock) |
552 | { |
553 | struct io_wq *wq = worker->wq; |
554 | bool do_kill = test_bit(IO_WQ_BIT_EXIT, &wq->state); |
555 | |
556 | do { |
557 | struct io_wq_work *work; |
558 | |
559 | /* |
560 | * If we got some work, mark us as busy. If we didn't, but |
561 | * the list isn't empty, it means we stalled on hashed work. |
562 | * Mark us stalled so we don't keep looking for work when we |
563 | * can't make progress, any work completion or insertion will |
564 | * clear the stalled flag. |
565 | */ |
566 | work = io_get_next_work(acct, worker); |
567 | raw_spin_unlock(&acct->lock); |
568 | if (work) { |
569 | __io_worker_busy(wq, worker); |
570 | |
571 | /* |
572 | * Make sure cancelation can find this, even before |
573 | * it becomes the active work. That avoids a window |
574 | * where the work has been removed from our general |
575 | * work list, but isn't yet discoverable as the |
576 | * current work item for this worker. |
577 | */ |
578 | raw_spin_lock(&worker->lock); |
579 | worker->next_work = work; |
580 | raw_spin_unlock(&worker->lock); |
581 | } else { |
582 | break; |
583 | } |
584 | io_assign_current_work(worker, work); |
585 | __set_current_state(TASK_RUNNING); |
586 | |
587 | /* handle a whole dependent link */ |
588 | do { |
589 | struct io_wq_work *next_hashed, *linked; |
590 | unsigned int hash = io_get_work_hash(work); |
591 | |
592 | next_hashed = wq_next_work(work); |
593 | |
594 | if (unlikely(do_kill) && (work->flags & IO_WQ_WORK_UNBOUND)) |
595 | work->flags |= IO_WQ_WORK_CANCEL; |
596 | wq->do_work(work); |
597 | io_assign_current_work(worker, NULL); |
598 | |
599 | linked = wq->free_work(work); |
600 | work = next_hashed; |
601 | if (!work && linked && !io_wq_is_hashed(work: linked)) { |
602 | work = linked; |
603 | linked = NULL; |
604 | } |
605 | io_assign_current_work(worker, work); |
606 | if (linked) |
607 | io_wq_enqueue(wq, work: linked); |
608 | |
609 | if (hash != -1U && !next_hashed) { |
610 | /* serialize hash clear with wake_up() */ |
611 | spin_lock_irq(lock: &wq->hash->wait.lock); |
612 | clear_bit(nr: hash, addr: &wq->hash->map); |
613 | clear_bit(nr: IO_ACCT_STALLED_BIT, addr: &acct->flags); |
614 | spin_unlock_irq(lock: &wq->hash->wait.lock); |
615 | if (wq_has_sleeper(wq_head: &wq->hash->wait)) |
616 | wake_up(&wq->hash->wait); |
617 | } |
618 | } while (work); |
619 | |
620 | if (!__io_acct_run_queue(acct)) |
621 | break; |
622 | raw_spin_lock(&acct->lock); |
623 | } while (1); |
624 | } |
625 | |
626 | static int io_wq_worker(void *data) |
627 | { |
628 | struct io_worker *worker = data; |
629 | struct io_wq_acct *acct = io_wq_get_acct(worker); |
630 | struct io_wq *wq = worker->wq; |
631 | bool exit_mask = false, last_timeout = false; |
632 | char buf[TASK_COMM_LEN]; |
633 | |
634 | worker->flags |= (IO_WORKER_F_UP | IO_WORKER_F_RUNNING); |
635 | |
636 | snprintf(buf, size: sizeof(buf), fmt: "iou-wrk-%d" , wq->task->pid); |
637 | set_task_comm(current, from: buf); |
638 | |
639 | while (!test_bit(IO_WQ_BIT_EXIT, &wq->state)) { |
640 | long ret; |
641 | |
642 | set_current_state(TASK_INTERRUPTIBLE); |
643 | |
644 | /* |
645 | * If we have work to do, io_acct_run_queue() returns with |
646 | * the acct->lock held. If not, it will drop it. |
647 | */ |
648 | while (io_acct_run_queue(acct)) |
649 | io_worker_handle_work(acct, worker); |
650 | |
651 | raw_spin_lock(&wq->lock); |
652 | /* |
653 | * Last sleep timed out. Exit if we're not the last worker, |
654 | * or if someone modified our affinity. |
655 | */ |
656 | if (last_timeout && (exit_mask || acct->nr_workers > 1)) { |
657 | acct->nr_workers--; |
658 | raw_spin_unlock(&wq->lock); |
659 | __set_current_state(TASK_RUNNING); |
660 | break; |
661 | } |
662 | last_timeout = false; |
663 | __io_worker_idle(wq, worker); |
664 | raw_spin_unlock(&wq->lock); |
665 | if (io_run_task_work()) |
666 | continue; |
667 | ret = schedule_timeout(WORKER_IDLE_TIMEOUT); |
668 | if (signal_pending(current)) { |
669 | struct ksignal ksig; |
670 | |
671 | if (!get_signal(ksig: &ksig)) |
672 | continue; |
673 | break; |
674 | } |
675 | if (!ret) { |
676 | last_timeout = true; |
677 | exit_mask = !cpumask_test_cpu(raw_smp_processor_id(), |
678 | cpumask: wq->cpu_mask); |
679 | } |
680 | } |
681 | |
682 | if (test_bit(IO_WQ_BIT_EXIT, &wq->state) && io_acct_run_queue(acct)) |
683 | io_worker_handle_work(acct, worker); |
684 | |
685 | io_worker_exit(worker); |
686 | return 0; |
687 | } |
688 | |
689 | /* |
690 | * Called when a worker is scheduled in. Mark us as currently running. |
691 | */ |
692 | void io_wq_worker_running(struct task_struct *tsk) |
693 | { |
694 | struct io_worker *worker = tsk->worker_private; |
695 | |
696 | if (!worker) |
697 | return; |
698 | if (!(worker->flags & IO_WORKER_F_UP)) |
699 | return; |
700 | if (worker->flags & IO_WORKER_F_RUNNING) |
701 | return; |
702 | worker->flags |= IO_WORKER_F_RUNNING; |
703 | io_wq_inc_running(worker); |
704 | } |
705 | |
706 | /* |
707 | * Called when worker is going to sleep. If there are no workers currently |
708 | * running and we have work pending, wake up a free one or create a new one. |
709 | */ |
710 | void io_wq_worker_sleeping(struct task_struct *tsk) |
711 | { |
712 | struct io_worker *worker = tsk->worker_private; |
713 | |
714 | if (!worker) |
715 | return; |
716 | if (!(worker->flags & IO_WORKER_F_UP)) |
717 | return; |
718 | if (!(worker->flags & IO_WORKER_F_RUNNING)) |
719 | return; |
720 | |
721 | worker->flags &= ~IO_WORKER_F_RUNNING; |
722 | io_wq_dec_running(worker); |
723 | } |
724 | |
725 | static void io_init_new_worker(struct io_wq *wq, struct io_worker *worker, |
726 | struct task_struct *tsk) |
727 | { |
728 | tsk->worker_private = worker; |
729 | worker->task = tsk; |
730 | set_cpus_allowed_ptr(p: tsk, new_mask: wq->cpu_mask); |
731 | |
732 | raw_spin_lock(&wq->lock); |
733 | hlist_nulls_add_head_rcu(n: &worker->nulls_node, h: &wq->free_list); |
734 | list_add_tail_rcu(new: &worker->all_list, head: &wq->all_list); |
735 | worker->flags |= IO_WORKER_F_FREE; |
736 | raw_spin_unlock(&wq->lock); |
737 | wake_up_new_task(tsk); |
738 | } |
739 | |
740 | static bool io_wq_work_match_all(struct io_wq_work *work, void *data) |
741 | { |
742 | return true; |
743 | } |
744 | |
745 | static inline bool io_should_retry_thread(long err) |
746 | { |
747 | /* |
748 | * Prevent perpetual task_work retry, if the task (or its group) is |
749 | * exiting. |
750 | */ |
751 | if (fatal_signal_pending(current)) |
752 | return false; |
753 | |
754 | switch (err) { |
755 | case -EAGAIN: |
756 | case -ERESTARTSYS: |
757 | case -ERESTARTNOINTR: |
758 | case -ERESTARTNOHAND: |
759 | return true; |
760 | default: |
761 | return false; |
762 | } |
763 | } |
764 | |
765 | static void create_worker_cont(struct callback_head *cb) |
766 | { |
767 | struct io_worker *worker; |
768 | struct task_struct *tsk; |
769 | struct io_wq *wq; |
770 | |
771 | worker = container_of(cb, struct io_worker, create_work); |
772 | clear_bit_unlock(nr: 0, addr: &worker->create_state); |
773 | wq = worker->wq; |
774 | tsk = create_io_thread(fn: io_wq_worker, arg: worker, NUMA_NO_NODE); |
775 | if (!IS_ERR(ptr: tsk)) { |
776 | io_init_new_worker(wq, worker, tsk); |
777 | io_worker_release(worker); |
778 | return; |
779 | } else if (!io_should_retry_thread(err: PTR_ERR(ptr: tsk))) { |
780 | struct io_wq_acct *acct = io_wq_get_acct(worker); |
781 | |
782 | atomic_dec(v: &acct->nr_running); |
783 | raw_spin_lock(&wq->lock); |
784 | acct->nr_workers--; |
785 | if (!acct->nr_workers) { |
786 | struct io_cb_cancel_data match = { |
787 | .fn = io_wq_work_match_all, |
788 | .cancel_all = true, |
789 | }; |
790 | |
791 | raw_spin_unlock(&wq->lock); |
792 | while (io_acct_cancel_pending_work(wq, acct, match: &match)) |
793 | ; |
794 | } else { |
795 | raw_spin_unlock(&wq->lock); |
796 | } |
797 | io_worker_ref_put(wq); |
798 | kfree(objp: worker); |
799 | return; |
800 | } |
801 | |
802 | /* re-create attempts grab a new worker ref, drop the existing one */ |
803 | io_worker_release(worker); |
804 | schedule_work(work: &worker->work); |
805 | } |
806 | |
807 | static void io_workqueue_create(struct work_struct *work) |
808 | { |
809 | struct io_worker *worker = container_of(work, struct io_worker, work); |
810 | struct io_wq_acct *acct = io_wq_get_acct(worker); |
811 | |
812 | if (!io_queue_worker_create(worker, acct, func: create_worker_cont)) |
813 | kfree(objp: worker); |
814 | } |
815 | |
816 | static bool create_io_worker(struct io_wq *wq, int index) |
817 | { |
818 | struct io_wq_acct *acct = &wq->acct[index]; |
819 | struct io_worker *worker; |
820 | struct task_struct *tsk; |
821 | |
822 | __set_current_state(TASK_RUNNING); |
823 | |
824 | worker = kzalloc(size: sizeof(*worker), GFP_KERNEL); |
825 | if (!worker) { |
826 | fail: |
827 | atomic_dec(v: &acct->nr_running); |
828 | raw_spin_lock(&wq->lock); |
829 | acct->nr_workers--; |
830 | raw_spin_unlock(&wq->lock); |
831 | io_worker_ref_put(wq); |
832 | return false; |
833 | } |
834 | |
835 | refcount_set(r: &worker->ref, n: 1); |
836 | worker->wq = wq; |
837 | raw_spin_lock_init(&worker->lock); |
838 | init_completion(x: &worker->ref_done); |
839 | |
840 | if (index == IO_WQ_ACCT_BOUND) |
841 | worker->flags |= IO_WORKER_F_BOUND; |
842 | |
843 | tsk = create_io_thread(fn: io_wq_worker, arg: worker, NUMA_NO_NODE); |
844 | if (!IS_ERR(ptr: tsk)) { |
845 | io_init_new_worker(wq, worker, tsk); |
846 | } else if (!io_should_retry_thread(err: PTR_ERR(ptr: tsk))) { |
847 | kfree(objp: worker); |
848 | goto fail; |
849 | } else { |
850 | INIT_WORK(&worker->work, io_workqueue_create); |
851 | schedule_work(work: &worker->work); |
852 | } |
853 | |
854 | return true; |
855 | } |
856 | |
857 | /* |
858 | * Iterate the passed in list and call the specific function for each |
859 | * worker that isn't exiting |
860 | */ |
861 | static bool io_wq_for_each_worker(struct io_wq *wq, |
862 | bool (*func)(struct io_worker *, void *), |
863 | void *data) |
864 | { |
865 | struct io_worker *worker; |
866 | bool ret = false; |
867 | |
868 | list_for_each_entry_rcu(worker, &wq->all_list, all_list) { |
869 | if (io_worker_get(worker)) { |
870 | /* no task if node is/was offline */ |
871 | if (worker->task) |
872 | ret = func(worker, data); |
873 | io_worker_release(worker); |
874 | if (ret) |
875 | break; |
876 | } |
877 | } |
878 | |
879 | return ret; |
880 | } |
881 | |
882 | static bool io_wq_worker_wake(struct io_worker *worker, void *data) |
883 | { |
884 | __set_notify_signal(task: worker->task); |
885 | wake_up_process(tsk: worker->task); |
886 | return false; |
887 | } |
888 | |
889 | static void io_run_cancel(struct io_wq_work *work, struct io_wq *wq) |
890 | { |
891 | do { |
892 | work->flags |= IO_WQ_WORK_CANCEL; |
893 | wq->do_work(work); |
894 | work = wq->free_work(work); |
895 | } while (work); |
896 | } |
897 | |
898 | static void io_wq_insert_work(struct io_wq *wq, struct io_wq_work *work) |
899 | { |
900 | struct io_wq_acct *acct = io_work_get_acct(wq, work); |
901 | unsigned int hash; |
902 | struct io_wq_work *tail; |
903 | |
904 | if (!io_wq_is_hashed(work)) { |
905 | append: |
906 | wq_list_add_tail(node: &work->list, list: &acct->work_list); |
907 | return; |
908 | } |
909 | |
910 | hash = io_get_work_hash(work); |
911 | tail = wq->hash_tail[hash]; |
912 | wq->hash_tail[hash] = work; |
913 | if (!tail) |
914 | goto append; |
915 | |
916 | wq_list_add_after(node: &work->list, pos: &tail->list, list: &acct->work_list); |
917 | } |
918 | |
919 | static bool io_wq_work_match_item(struct io_wq_work *work, void *data) |
920 | { |
921 | return work == data; |
922 | } |
923 | |
924 | void io_wq_enqueue(struct io_wq *wq, struct io_wq_work *work) |
925 | { |
926 | struct io_wq_acct *acct = io_work_get_acct(wq, work); |
927 | struct io_cb_cancel_data match; |
928 | unsigned work_flags = work->flags; |
929 | bool do_create; |
930 | |
931 | /* |
932 | * If io-wq is exiting for this task, or if the request has explicitly |
933 | * been marked as one that should not get executed, cancel it here. |
934 | */ |
935 | if (test_bit(IO_WQ_BIT_EXIT, &wq->state) || |
936 | (work->flags & IO_WQ_WORK_CANCEL)) { |
937 | io_run_cancel(work, wq); |
938 | return; |
939 | } |
940 | |
941 | raw_spin_lock(&acct->lock); |
942 | io_wq_insert_work(wq, work); |
943 | clear_bit(nr: IO_ACCT_STALLED_BIT, addr: &acct->flags); |
944 | raw_spin_unlock(&acct->lock); |
945 | |
946 | rcu_read_lock(); |
947 | do_create = !io_wq_activate_free_worker(wq, acct); |
948 | rcu_read_unlock(); |
949 | |
950 | if (do_create && ((work_flags & IO_WQ_WORK_CONCURRENT) || |
951 | !atomic_read(v: &acct->nr_running))) { |
952 | bool did_create; |
953 | |
954 | did_create = io_wq_create_worker(wq, acct); |
955 | if (likely(did_create)) |
956 | return; |
957 | |
958 | raw_spin_lock(&wq->lock); |
959 | if (acct->nr_workers) { |
960 | raw_spin_unlock(&wq->lock); |
961 | return; |
962 | } |
963 | raw_spin_unlock(&wq->lock); |
964 | |
965 | /* fatal condition, failed to create the first worker */ |
966 | match.fn = io_wq_work_match_item, |
967 | match.data = work, |
968 | match.cancel_all = false, |
969 | |
970 | io_acct_cancel_pending_work(wq, acct, match: &match); |
971 | } |
972 | } |
973 | |
974 | /* |
975 | * Work items that hash to the same value will not be done in parallel. |
976 | * Used to limit concurrent writes, generally hashed by inode. |
977 | */ |
978 | void io_wq_hash_work(struct io_wq_work *work, void *val) |
979 | { |
980 | unsigned int bit; |
981 | |
982 | bit = hash_ptr(ptr: val, IO_WQ_HASH_ORDER); |
983 | work->flags |= (IO_WQ_WORK_HASHED | (bit << IO_WQ_HASH_SHIFT)); |
984 | } |
985 | |
986 | static bool __io_wq_worker_cancel(struct io_worker *worker, |
987 | struct io_cb_cancel_data *match, |
988 | struct io_wq_work *work) |
989 | { |
990 | if (work && match->fn(work, match->data)) { |
991 | work->flags |= IO_WQ_WORK_CANCEL; |
992 | __set_notify_signal(task: worker->task); |
993 | return true; |
994 | } |
995 | |
996 | return false; |
997 | } |
998 | |
999 | static bool io_wq_worker_cancel(struct io_worker *worker, void *data) |
1000 | { |
1001 | struct io_cb_cancel_data *match = data; |
1002 | |
1003 | /* |
1004 | * Hold the lock to avoid ->cur_work going out of scope, caller |
1005 | * may dereference the passed in work. |
1006 | */ |
1007 | raw_spin_lock(&worker->lock); |
1008 | if (__io_wq_worker_cancel(worker, match, work: worker->cur_work) || |
1009 | __io_wq_worker_cancel(worker, match, work: worker->next_work)) |
1010 | match->nr_running++; |
1011 | raw_spin_unlock(&worker->lock); |
1012 | |
1013 | return match->nr_running && !match->cancel_all; |
1014 | } |
1015 | |
1016 | static inline void io_wq_remove_pending(struct io_wq *wq, |
1017 | struct io_wq_work *work, |
1018 | struct io_wq_work_node *prev) |
1019 | { |
1020 | struct io_wq_acct *acct = io_work_get_acct(wq, work); |
1021 | unsigned int hash = io_get_work_hash(work); |
1022 | struct io_wq_work *prev_work = NULL; |
1023 | |
1024 | if (io_wq_is_hashed(work) && work == wq->hash_tail[hash]) { |
1025 | if (prev) |
1026 | prev_work = container_of(prev, struct io_wq_work, list); |
1027 | if (prev_work && io_get_work_hash(work: prev_work) == hash) |
1028 | wq->hash_tail[hash] = prev_work; |
1029 | else |
1030 | wq->hash_tail[hash] = NULL; |
1031 | } |
1032 | wq_list_del(list: &acct->work_list, node: &work->list, prev); |
1033 | } |
1034 | |
1035 | static bool io_acct_cancel_pending_work(struct io_wq *wq, |
1036 | struct io_wq_acct *acct, |
1037 | struct io_cb_cancel_data *match) |
1038 | { |
1039 | struct io_wq_work_node *node, *prev; |
1040 | struct io_wq_work *work; |
1041 | |
1042 | raw_spin_lock(&acct->lock); |
1043 | wq_list_for_each(node, prev, &acct->work_list) { |
1044 | work = container_of(node, struct io_wq_work, list); |
1045 | if (!match->fn(work, match->data)) |
1046 | continue; |
1047 | io_wq_remove_pending(wq, work, prev); |
1048 | raw_spin_unlock(&acct->lock); |
1049 | io_run_cancel(work, wq); |
1050 | match->nr_pending++; |
1051 | /* not safe to continue after unlock */ |
1052 | return true; |
1053 | } |
1054 | raw_spin_unlock(&acct->lock); |
1055 | |
1056 | return false; |
1057 | } |
1058 | |
1059 | static void io_wq_cancel_pending_work(struct io_wq *wq, |
1060 | struct io_cb_cancel_data *match) |
1061 | { |
1062 | int i; |
1063 | retry: |
1064 | for (i = 0; i < IO_WQ_ACCT_NR; i++) { |
1065 | struct io_wq_acct *acct = io_get_acct(wq, bound: i == 0); |
1066 | |
1067 | if (io_acct_cancel_pending_work(wq, acct, match)) { |
1068 | if (match->cancel_all) |
1069 | goto retry; |
1070 | break; |
1071 | } |
1072 | } |
1073 | } |
1074 | |
1075 | static void io_wq_cancel_running_work(struct io_wq *wq, |
1076 | struct io_cb_cancel_data *match) |
1077 | { |
1078 | rcu_read_lock(); |
1079 | io_wq_for_each_worker(wq, func: io_wq_worker_cancel, data: match); |
1080 | rcu_read_unlock(); |
1081 | } |
1082 | |
1083 | enum io_wq_cancel io_wq_cancel_cb(struct io_wq *wq, work_cancel_fn *cancel, |
1084 | void *data, bool cancel_all) |
1085 | { |
1086 | struct io_cb_cancel_data match = { |
1087 | .fn = cancel, |
1088 | .data = data, |
1089 | .cancel_all = cancel_all, |
1090 | }; |
1091 | |
1092 | /* |
1093 | * First check pending list, if we're lucky we can just remove it |
1094 | * from there. CANCEL_OK means that the work is returned as-new, |
1095 | * no completion will be posted for it. |
1096 | * |
1097 | * Then check if a free (going busy) or busy worker has the work |
1098 | * currently running. If we find it there, we'll return CANCEL_RUNNING |
1099 | * as an indication that we attempt to signal cancellation. The |
1100 | * completion will run normally in this case. |
1101 | * |
1102 | * Do both of these while holding the wq->lock, to ensure that |
1103 | * we'll find a work item regardless of state. |
1104 | */ |
1105 | io_wq_cancel_pending_work(wq, match: &match); |
1106 | if (match.nr_pending && !match.cancel_all) |
1107 | return IO_WQ_CANCEL_OK; |
1108 | |
1109 | raw_spin_lock(&wq->lock); |
1110 | io_wq_cancel_running_work(wq, match: &match); |
1111 | raw_spin_unlock(&wq->lock); |
1112 | if (match.nr_running && !match.cancel_all) |
1113 | return IO_WQ_CANCEL_RUNNING; |
1114 | |
1115 | if (match.nr_running) |
1116 | return IO_WQ_CANCEL_RUNNING; |
1117 | if (match.nr_pending) |
1118 | return IO_WQ_CANCEL_OK; |
1119 | return IO_WQ_CANCEL_NOTFOUND; |
1120 | } |
1121 | |
1122 | static int io_wq_hash_wake(struct wait_queue_entry *wait, unsigned mode, |
1123 | int sync, void *key) |
1124 | { |
1125 | struct io_wq *wq = container_of(wait, struct io_wq, wait); |
1126 | int i; |
1127 | |
1128 | list_del_init(entry: &wait->entry); |
1129 | |
1130 | rcu_read_lock(); |
1131 | for (i = 0; i < IO_WQ_ACCT_NR; i++) { |
1132 | struct io_wq_acct *acct = &wq->acct[i]; |
1133 | |
1134 | if (test_and_clear_bit(nr: IO_ACCT_STALLED_BIT, addr: &acct->flags)) |
1135 | io_wq_activate_free_worker(wq, acct); |
1136 | } |
1137 | rcu_read_unlock(); |
1138 | return 1; |
1139 | } |
1140 | |
1141 | struct io_wq *io_wq_create(unsigned bounded, struct io_wq_data *data) |
1142 | { |
1143 | int ret, i; |
1144 | struct io_wq *wq; |
1145 | |
1146 | if (WARN_ON_ONCE(!data->free_work || !data->do_work)) |
1147 | return ERR_PTR(error: -EINVAL); |
1148 | if (WARN_ON_ONCE(!bounded)) |
1149 | return ERR_PTR(error: -EINVAL); |
1150 | |
1151 | wq = kzalloc(size: sizeof(struct io_wq), GFP_KERNEL); |
1152 | if (!wq) |
1153 | return ERR_PTR(error: -ENOMEM); |
1154 | |
1155 | refcount_inc(r: &data->hash->refs); |
1156 | wq->hash = data->hash; |
1157 | wq->free_work = data->free_work; |
1158 | wq->do_work = data->do_work; |
1159 | |
1160 | ret = -ENOMEM; |
1161 | |
1162 | if (!alloc_cpumask_var(mask: &wq->cpu_mask, GFP_KERNEL)) |
1163 | goto err; |
1164 | cpumask_copy(dstp: wq->cpu_mask, cpu_possible_mask); |
1165 | wq->acct[IO_WQ_ACCT_BOUND].max_workers = bounded; |
1166 | wq->acct[IO_WQ_ACCT_UNBOUND].max_workers = |
1167 | task_rlimit(current, RLIMIT_NPROC); |
1168 | INIT_LIST_HEAD(list: &wq->wait.entry); |
1169 | wq->wait.func = io_wq_hash_wake; |
1170 | for (i = 0; i < IO_WQ_ACCT_NR; i++) { |
1171 | struct io_wq_acct *acct = &wq->acct[i]; |
1172 | |
1173 | acct->index = i; |
1174 | atomic_set(v: &acct->nr_running, i: 0); |
1175 | INIT_WQ_LIST(&acct->work_list); |
1176 | raw_spin_lock_init(&acct->lock); |
1177 | } |
1178 | |
1179 | raw_spin_lock_init(&wq->lock); |
1180 | INIT_HLIST_NULLS_HEAD(&wq->free_list, 0); |
1181 | INIT_LIST_HEAD(list: &wq->all_list); |
1182 | |
1183 | wq->task = get_task_struct(t: data->task); |
1184 | atomic_set(v: &wq->worker_refs, i: 1); |
1185 | init_completion(x: &wq->worker_done); |
1186 | ret = cpuhp_state_add_instance_nocalls(state: io_wq_online, node: &wq->cpuhp_node); |
1187 | if (ret) |
1188 | goto err; |
1189 | |
1190 | return wq; |
1191 | err: |
1192 | io_wq_put_hash(hash: data->hash); |
1193 | free_cpumask_var(mask: wq->cpu_mask); |
1194 | kfree(objp: wq); |
1195 | return ERR_PTR(error: ret); |
1196 | } |
1197 | |
1198 | static bool io_task_work_match(struct callback_head *cb, void *data) |
1199 | { |
1200 | struct io_worker *worker; |
1201 | |
1202 | if (cb->func != create_worker_cb && cb->func != create_worker_cont) |
1203 | return false; |
1204 | worker = container_of(cb, struct io_worker, create_work); |
1205 | return worker->wq == data; |
1206 | } |
1207 | |
1208 | void io_wq_exit_start(struct io_wq *wq) |
1209 | { |
1210 | set_bit(nr: IO_WQ_BIT_EXIT, addr: &wq->state); |
1211 | } |
1212 | |
1213 | static void io_wq_cancel_tw_create(struct io_wq *wq) |
1214 | { |
1215 | struct callback_head *cb; |
1216 | |
1217 | while ((cb = task_work_cancel_match(task: wq->task, match: io_task_work_match, data: wq)) != NULL) { |
1218 | struct io_worker *worker; |
1219 | |
1220 | worker = container_of(cb, struct io_worker, create_work); |
1221 | io_worker_cancel_cb(worker); |
1222 | /* |
1223 | * Only the worker continuation helper has worker allocated and |
1224 | * hence needs freeing. |
1225 | */ |
1226 | if (cb->func == create_worker_cont) |
1227 | kfree(objp: worker); |
1228 | } |
1229 | } |
1230 | |
1231 | static void io_wq_exit_workers(struct io_wq *wq) |
1232 | { |
1233 | if (!wq->task) |
1234 | return; |
1235 | |
1236 | io_wq_cancel_tw_create(wq); |
1237 | |
1238 | rcu_read_lock(); |
1239 | io_wq_for_each_worker(wq, func: io_wq_worker_wake, NULL); |
1240 | rcu_read_unlock(); |
1241 | io_worker_ref_put(wq); |
1242 | wait_for_completion(&wq->worker_done); |
1243 | |
1244 | spin_lock_irq(lock: &wq->hash->wait.lock); |
1245 | list_del_init(entry: &wq->wait.entry); |
1246 | spin_unlock_irq(lock: &wq->hash->wait.lock); |
1247 | |
1248 | put_task_struct(t: wq->task); |
1249 | wq->task = NULL; |
1250 | } |
1251 | |
1252 | static void io_wq_destroy(struct io_wq *wq) |
1253 | { |
1254 | struct io_cb_cancel_data match = { |
1255 | .fn = io_wq_work_match_all, |
1256 | .cancel_all = true, |
1257 | }; |
1258 | |
1259 | cpuhp_state_remove_instance_nocalls(state: io_wq_online, node: &wq->cpuhp_node); |
1260 | io_wq_cancel_pending_work(wq, match: &match); |
1261 | free_cpumask_var(mask: wq->cpu_mask); |
1262 | io_wq_put_hash(hash: wq->hash); |
1263 | kfree(objp: wq); |
1264 | } |
1265 | |
1266 | void io_wq_put_and_exit(struct io_wq *wq) |
1267 | { |
1268 | WARN_ON_ONCE(!test_bit(IO_WQ_BIT_EXIT, &wq->state)); |
1269 | |
1270 | io_wq_exit_workers(wq); |
1271 | io_wq_destroy(wq); |
1272 | } |
1273 | |
1274 | struct online_data { |
1275 | unsigned int cpu; |
1276 | bool online; |
1277 | }; |
1278 | |
1279 | static bool io_wq_worker_affinity(struct io_worker *worker, void *data) |
1280 | { |
1281 | struct online_data *od = data; |
1282 | |
1283 | if (od->online) |
1284 | cpumask_set_cpu(cpu: od->cpu, dstp: worker->wq->cpu_mask); |
1285 | else |
1286 | cpumask_clear_cpu(cpu: od->cpu, dstp: worker->wq->cpu_mask); |
1287 | return false; |
1288 | } |
1289 | |
1290 | static int __io_wq_cpu_online(struct io_wq *wq, unsigned int cpu, bool online) |
1291 | { |
1292 | struct online_data od = { |
1293 | .cpu = cpu, |
1294 | .online = online |
1295 | }; |
1296 | |
1297 | rcu_read_lock(); |
1298 | io_wq_for_each_worker(wq, func: io_wq_worker_affinity, data: &od); |
1299 | rcu_read_unlock(); |
1300 | return 0; |
1301 | } |
1302 | |
1303 | static int io_wq_cpu_online(unsigned int cpu, struct hlist_node *node) |
1304 | { |
1305 | struct io_wq *wq = hlist_entry_safe(node, struct io_wq, cpuhp_node); |
1306 | |
1307 | return __io_wq_cpu_online(wq, cpu, online: true); |
1308 | } |
1309 | |
1310 | static int io_wq_cpu_offline(unsigned int cpu, struct hlist_node *node) |
1311 | { |
1312 | struct io_wq *wq = hlist_entry_safe(node, struct io_wq, cpuhp_node); |
1313 | |
1314 | return __io_wq_cpu_online(wq, cpu, online: false); |
1315 | } |
1316 | |
1317 | int io_wq_cpu_affinity(struct io_uring_task *tctx, cpumask_var_t mask) |
1318 | { |
1319 | if (!tctx || !tctx->io_wq) |
1320 | return -EINVAL; |
1321 | |
1322 | rcu_read_lock(); |
1323 | if (mask) |
1324 | cpumask_copy(dstp: tctx->io_wq->cpu_mask, srcp: mask); |
1325 | else |
1326 | cpumask_copy(dstp: tctx->io_wq->cpu_mask, cpu_possible_mask); |
1327 | rcu_read_unlock(); |
1328 | |
1329 | return 0; |
1330 | } |
1331 | |
1332 | /* |
1333 | * Set max number of unbounded workers, returns old value. If new_count is 0, |
1334 | * then just return the old value. |
1335 | */ |
1336 | int io_wq_max_workers(struct io_wq *wq, int *new_count) |
1337 | { |
1338 | struct io_wq_acct *acct; |
1339 | int prev[IO_WQ_ACCT_NR]; |
1340 | int i; |
1341 | |
1342 | BUILD_BUG_ON((int) IO_WQ_ACCT_BOUND != (int) IO_WQ_BOUND); |
1343 | BUILD_BUG_ON((int) IO_WQ_ACCT_UNBOUND != (int) IO_WQ_UNBOUND); |
1344 | BUILD_BUG_ON((int) IO_WQ_ACCT_NR != 2); |
1345 | |
1346 | for (i = 0; i < IO_WQ_ACCT_NR; i++) { |
1347 | if (new_count[i] > task_rlimit(current, RLIMIT_NPROC)) |
1348 | new_count[i] = task_rlimit(current, RLIMIT_NPROC); |
1349 | } |
1350 | |
1351 | for (i = 0; i < IO_WQ_ACCT_NR; i++) |
1352 | prev[i] = 0; |
1353 | |
1354 | rcu_read_lock(); |
1355 | |
1356 | raw_spin_lock(&wq->lock); |
1357 | for (i = 0; i < IO_WQ_ACCT_NR; i++) { |
1358 | acct = &wq->acct[i]; |
1359 | prev[i] = max_t(int, acct->max_workers, prev[i]); |
1360 | if (new_count[i]) |
1361 | acct->max_workers = new_count[i]; |
1362 | } |
1363 | raw_spin_unlock(&wq->lock); |
1364 | rcu_read_unlock(); |
1365 | |
1366 | for (i = 0; i < IO_WQ_ACCT_NR; i++) |
1367 | new_count[i] = prev[i]; |
1368 | |
1369 | return 0; |
1370 | } |
1371 | |
1372 | static __init int io_wq_init(void) |
1373 | { |
1374 | int ret; |
1375 | |
1376 | ret = cpuhp_setup_state_multi(state: CPUHP_AP_ONLINE_DYN, name: "io-wq/online" , |
1377 | startup: io_wq_cpu_online, teardown: io_wq_cpu_offline); |
1378 | if (ret < 0) |
1379 | return ret; |
1380 | io_wq_online = ret; |
1381 | return 0; |
1382 | } |
1383 | subsys_initcall(io_wq_init); |
1384 | |